Relay for tripping a circuit breaker



Jan. 31, 1967 H. P. FRANZ RELAY FOR TRIPPING A CIRCUIT BREAKER 2 SheetsSheet 1 Filed July 6, 1965 l/l/VEA/I'OR HENRY P. FRANZ Jan. 31, 1967 PJFRANZ 3,302,139

RELAY FOR TRIPPING A CIRCUIT BREAKER Filed July 1965 2 Sheets-Sheet 2 Vl/E/VTO/P. HEN RY P. FRANZ W H/S A TTO/P/VEVJ.

United States Patent 6 Electric Company, Trenton, N.J., a corporation of New Jersey Filed July 6, 1965, Ser. No. 469,536 6 Claims. (Cl. 335-13) This invention relates to electrical relays and particularly to relays sensitive to undervoltage to trip an associated circuit breaker unit upon the occurrence of such undervoltage for automatic opening of the circuit breaker contacts.

Since in other instances electrical relays are desired, in combination with circuit breaker units, to trip the circuit breaker units either when the relay coils are energized above a predetermined voltage, or for remote tripping by energizing the relays momentarily, it is desirable to construct an undervoltage relay from components which can be readily adapted to an overvoltage or remotely tripping relay.

Therefore, it is an object of this invention to provide an electrical relay for tripping a circuit breaker unit upon undervoltage, the relay being made of components which can be easily converted to a relay for overvoltage or remote tripping of the circuit breaker.

In a pending US. patent application, Serial No. 276,- 575, filed April 29, 1963, now Patent Number 3,264,428, there is disclosed an undervoltage relay that will automatically reset itself to the position before the occurrence of the undervoltage upon the return to the relay coil of a predetermined voltage level (pickup voltage), in combination with a circuit breaker unit having a circuit breaker armature for controlling the circuit breaker linkage mechanism in which both, i.e., the circuit breaker armature and the circuit breaker linkage, automatically reset themselves to positions wherein the circuit breaker contacts can be manually, directly moved to the closed position without an intermediate reset position after tripping takes place.

The present invention is a modification of the structure disclosed in the aforementioned pending US. patent application Serial No. 276,575, now Patent Number 3,264,- 428.

As in the structure disclosed in the aforementioned patent application, the present invention provides an undervoltage relay attached to the case of a circuit breaker unit, the relay comprising an electromagnetic coil mounted upon one leg of a U-shaped core formed by a plurality of stacked laminations, the other leg of the core supporting the relay armature. In the present invention the relay armature controls, but does not include, the trip finger which in turn actuates the armature of the associated circuit breaker unit.

In the present invention, the trip finger is movable into engagement with the circuit breaker armature to trip the associated circuit breaker linkage, this movement taking place when the relay is arranged for undervoltage sensing under the pressure of a spring connected to the relay armature, but the movement takes place when the relay is arranged for overvolt-age sensing, or remote tripping, due to the electromagnetic force on the relay armature.

The trip finger is pivotally mounted independently of the relay armature, but connected to the relay armature by a substantially rigid link, the link being pivotally connected at its opposite ends to the relay armature and to the trip finger. The trip finger is pivotally connected to a support or bracket mounted within the relay. A tension spring is connected at one end to the armature and at the other end to a spring support or bracket to bias the relay armature away from the end of the core to which the electromagnetic force of the relay coil tends to attract the armature.

The pivotal connection of this link to the trip finger and the pivotal connection of the trip finger to the support or bracket may be interchanged, while the spring bias on the relay armature remains substantially the same, and when interchanged results in the spring force biasing the trip finger in the opposite direction. For example, for use as an undervoltage relay, the link between the armature and the trip finger is disposed above the pivotal connection between the trip finger and its support. With this arrangement the trip finger is biased by the link and the spring in a counterclockwise direction at all times about the pivotal connection of the trip finger to its support, i.e., toward the associated circuit breaker armature.

On the other hand, for use as an overvoltage or remote tripping relay, the link between the trip finger and the armature is placed below the pivotal connection between the trip finger and its support. With such an arrangement, the link and the spring, whose location has not beenchanged, and which is therefore still biasing the armature away from the end of the core to which the electromagnetic flux tends to attract it, biases the trip finger in a clockwise direction away from the circuit breaker armature, i.e., away from the associated circuit breaker armature.

The spring bias on the link, in both positions of the link, tends to move the link in the same direction, but by moving the end of the link connected to the trip finger above or below the pivotal connection of the trip finger to its support, the direction in which the trip finger is biased by the spring is reversed.

Thus, it will be noted that the mechanical parts of the relay are the same for the different embodiments and what merely changes is their relative location to result in either an undervoltage relay, an overvoltage relay, or a remote tripping relay.

To summarize the relay when arranged as an undervoltage relay, the spring being under tension at all times, always tends to bias the relay armature in the direction which will cause engagement of the trip finger with the associated circuit breaker armature, but at rated voltage the electromagnetic flux is sufiicient to produce a force on the relay armature opposite in direction, and greater than, the spring force to maintain the relay armature attracted toward the core, whereby the trip finger is held in spaced relation with the circuit breaker armature. Upon the tripout undervoltage, the spring force is greater than the electromagnetic force on the relay armature and moves the relay armature and the trip finger to trip the circuit breaker, but when the pickup voltage returns to the relay coil, the relay armature and the trip finger automatically reset, because the electromagnetic flux on the relay armature, at such time, again becomes greater than the spring force thereon. When the relay armature and trip finger reset, the disengagement which results between the trip finger and the circuit breaker armature allows the circuit breaker armature to reset which in turn allows the circuit breaker linkage to automatically reset, permitting hte circuit breaker contacts to be reclosed, if desired.

To summarize the relay when arranged as an overvoltage or remote tripping relay, the relay spring being under tension at all times, now biases the relay armature in the direction which will cause the relay trip finger to be spaced from the circuit breaker armature. Upon an overvoltage in the relay coil, or if a remotely tripping relay, upon its energization, the electromagnetic flux is suificient to produce a force on the relay armature opposite in direction and greater than the spring force, whereupon the relay armature is attracted toward the core. Such movement of the relay armature causes the trip finger to be moved against its spring bias to bring the trip finger into engagement with the circuit breaker armature, turning the circuit breaker armature sufliciently to trip the circuit breaker linkage. Upon the return of the rated voltage, or upon deenergization of the coil if it is a remotely tripping relay, the armature returns to its initial position under the influence of the relay spring, i.e., the spring force now returns the armature and the trip finger to their initial positions, whereupon the trip finger becomes spaced from the armature of the circuit breaker unit, permitting the circuit breaker armature to be reset automatically, which in turn allows the circuit breaker linkage to automatically reset, and the circuit breaker contacts to be reclosed, if desired.

The foregoing and other objects of the invention, the principles of the invention, and the best modes in which it is contemplated applying such principles will more fully appear from the following description and accompanying drawings in illustration thereof.

In the drawings:

FIG. 1 is a perspective view of a relay for undervoltage tripping of a circuit breaker unit, the relay being constructed in accordance with this invention and showing the trip finger spaced from the associated circuit breaker armature, i.e., the rated voltage position of the relay, the remainder of the circuit breaker unit and the cover of the relay being omitted;

FIG. 2 is an end view taken along the line 2-2 in FIG. 1, but, unlike FIG. 1, showing the part of the circuit breaker case to which the relay is attached and showing, as in FIG. 1, the position of the relay trip finger when the relay is energized at about rated voltage and also partially showing the associated circuit breaker armature;

FIG. 3 is an end view similar to FIG. 2, but illustrating the actuated position of the trip finger, i.e., the position of the trip finger after the occurrence of a tripout undervoltage condition;

FIG. 4 is a bottom view of the relay illustrated in FIG. 1;

FIG. 5 is a partial, sectional view taken along the line 5-5 in FIG. 4, showing a part of the trip finger in elevation;

FIG. 6 is a view similar to FIG. 3, but illustrating the relay modified for overvoltage or remote tripping of the circuit breaker unit and in the actuated position during overvoltage or during energization for remote tripping; and

FIG. 7 is a partial, sectional view taken along the line 77 in FIG. 6.

Referring to the drawings, FIG. 1 illustrates an undervoltage relay 10, that is, a relay which will be actuated upon a suflicient decrease in the voltage energizing the relay coil 14, and the relays mechanism, as hereinafter described, is attached to a case 12 (FIGS. 2 and 3) of a suitable automatically resettable circuit breaker unit, the circuit breaker unit not being illustrated in the drawings, except for a part of the armature 40 thereof. The relay 10 includes a cover (not illustrated) enclosing, in conjunction with the circuit breaker case (not shown in detail), the relays mechanism. The relay cover is of molded insulation material similar to the material of the case 12 of the circuit breaker unit, the relay cover being suitably secured to the case 12.

As illustrated, the relay 10 comprises an armature (or clapper) 22 controlling a trip rod or trip finger 35 which on a predetermined drop in the electrical voltage at the relay engages and pivots the circuit breaker armature 40 to open the contacts (not illustrated) of the circuit breaker unit. For this purpose, the trip finger 35, as illustrated generally in FIGS. 2 and 3, extends upwardly through an elongated hole 42 in the circuit breaker case 12 and into association with the circuit breaker armature 40. The circuit breaker unit with which this relay has been used is of the automatically resettable type and the circuit breaker unit is generally described in copending US. patent application Serial No. 109,914. In view of the foregoing, the circuit breaker unit will not be described in detail herein.

The coil 14 of the relay 10 is wound about an insulator bobbin and mounted upon a leg 16 of an inverted U- shaped core 18, the latter being formed from magnetizable stacked laminations, preferably of high silicone steel. The relay armature 22 comprises two generally L- shaped plates 24 and 25, preferably of nonmagnetic material, such as brass, and spaced from each other. Placed between the lower ends (FIG. 1) of the plates 24 and 25 are generally rectangular, stacked clapper laminations 28 of magnetizable material, preferably of high silicone steel.

The trip finger 35 is pivotally connected by a pin 74 to a support formed by a tab 73 integral with the plate 55 and bent at about 90 to the main portion thereof, the pin 74 extending through a hole 72 in the tab 73 and a suitable hole 78 in the trip finger 35 and the pin 74 being headed at one end and flared over, after assembly, at the other end, so as to prevent its dropping out. The plate 55 forms another support at a second tab 83 having 'a hole 84, the tab 83 being bent also at about 90 to the main part of the plate 55 but extending in the opposite direction to the tab 73 and for a purpose to be described in connection with FIGS. 6 and 7.

Preferably, the trip finger 35 is generally flat, formed of insulation material, and the portion extending within the circuit breaker case 12 has an upper part disposed at 'an angle to the main portion of the trip finger 35, as illustrated, and engageable with the circuit breaker armature 40. Normally, that is, when the coil 14 is energized at approximately rated or normal voltage, and above, the trip finger 35 is held spaced from the associated circuit breaker armature 40 by a substantially rigid link 75 which is pivotally connected at one end to the upper plate 25 by a pin 76 extending through the plates 24 and 25, and connected at the other end by another pin 77 extending through a suitable hole 79 in the trip finger 35, the pins 76 and 77 being headed at one end and flared over at the other end. To facilitate the transfer of motion between the armature 22 and the trip finger 35 the link 75 is twisted, as shown.

The two far ends, as seen in FIG. 1, of the plates 24 .and 25 are connected together by an end plate 80, preferably of insulation material, with tab portions of the armature plates 24 and 25 extending through holes in the plate 80, the end tab portions of plates 24 and 25 being thereafter split and bent over, as illustrated in FIGS. 2 and 3.

The trip finger 35 is biased at all times toward engagement with the circuit breaker armature 40 by a tension spring 45, one end of the spring 45 being attached to the end plate 80 between the two plates 24 and 25 and the other end being attached to a spring support or bracket 48 by extending through a hole in a depending, FIGS. 2 and 3, bendable (to vary the spring tension somewhat) arm 50 of the bracket 48, the latter having a second arm 51 secured by suitable rivets to the core 18. Further, the bracket 48 has a third arm 52 which may be secured to the circuit breaker case 12 by suitable screws.

The plates 55 and 56 jointly form another support or bracket 20 and are both secured, by suitable rivets, to the core leg 19 and are preferably of non-magnetic material such as brass. The upper plate 56 and the lower plate 55, as seen in FIG. 1, extend between the armature plates 24 and 25. The plates 56 and 55 have lower ends 56a and 55a, respectively, with aligned holes through which extends a pin 58, the pin 58 also extending through other aligned, coaxial holes in the armature plates 24 and 25, to pivotally connect the armature 22 to the plates 55 and 56. The pin 58 has, at one end, an enlarged head and at the other end is flared over to prevent its dropping out.

The plate 56 is integral with an arm 60 and a foot 61 Which jointly define a U-shape, as generally illustrated in FIG. 1, the foot 61 having a hole through which a screw extends, FIGS. 3 and 2, to secure the foot 61 to thecase 12.

As illustrated in FIG. 2, during normal or rated voltage conditions the upper part of the trip finger 35 is disposed opposed to and spaced from the circuit breaker armature 40. On the occurrence of a predetermined tripout undervoltage, the armature laminations 28 move away from the legs 16 and 19 under pressure of the spring 45, the armature pivoting in a horizontal plane about the pin 58 and moving the link 75 to the left, as viewed in FIGS. 2 and 3. Since the link 75 is connected to the trip finger 35 above the pin 74, movement of the link 75 to the left causes the trip finger 35 to pivot counterclockwise in a vertical plane, due to the bias of the spring 45, toward the armature 40, until the trip finger 35 engages the circuit breaker armature 40 and moves it in the direction to release the linkage of the circuit breaker unit, whereupon the circuit breaker contacts (not shown) open.

Assuming the circuit breaker unit with which the relay coil 14 is associated to be a three pole unit, the relay coil 14 is connected electrically directly across two phases of the three phase system, the normal phase-to-phase voltage being the rated voltage of the relay coil 14. The circuit breaker coil, not illustrated, is connected, in series wit-h the return line to the opposite phase through the load. Thus, normally the relay coil 14 is energized at phase-to-phase voltage and the circuit breaker coil is energized at phase-to-phase voltage minus the voltage drop of the load. At rated voltage, the electromagnetic flux produced by the relay coil 14 is sufficient to overcome the force of the spring 45, and the armature 22 remains at such time in the position of FIG. 2. (The relay coil 14 could be constructed so as to have a rated voltage at a predetermined percentage of the phase-tophase voltage rating, but the various parts of the relay would have to be proportioned and/ or adjusted for this condition.) When the phase-to-phase voltage decreases below the normal voltage to be a first predetermined or tripout level, the electromagnetic force on the armature 22 is insufficient to overcome the force of the spring 45 in the opposite direction and the armature 22 is pivoted by the spring force to the position illustrated by FIG. 3, this being the tripped position of the relay.

Upon an increase in the phase-to-phase voltage, toward the normal voltage, the flux will increase to a second predetermined or pickup level at which time magnetic force on the armature 22 exceeds the force of the spring 45 sufficiently to pivot the armature 22 back to the position illustrated in FIGS. 1 and 2.

The aforedescribed and illustrated undervoltage relay is made from components that can be easily adapted for an overvoltage or remote tripping relay. Referring to FIGS. 6 and 7, the arrangement of the various parts for either an overvoltage or remote tripping relay is illustrated. The corresponding parts have been given the same number but a prime mark has been added in FIGS. 6 and 7. Of course, the coil 14 of the relay is constructed to suit either the overvoltage application or the remote tripping application, as the case may be.

To adapt the relay for overvoltage or remote tripping, the trip finger 35' is pivoted to the tab 83' by extending the pin 74 through the hole 79' in the finger 35 and through the hole 84' in the tab 83'. The link 75 is pivotally connected to the armature 22 immediately below the plate 24, as shown in FIG. 6, by the pin 76 and the link 75' extends toward the trip finger 35 to be pivotally connected at its opposite end by the pin 77 which extends through the link 75 and the hole 78' in the trip finger 35', i.e., below the pin 74'. It is noted, that the spring 45', in the embodiment of FIGS. 6 and 7, remains in the same position as in the embodiment of FIGS. 1 to 5, but because the connection between the armature 6 and the trip finger is now below the pin about which the trip finger pivots, instead of above it, the trip finger is now biased by the spring in the clockwise direction in- ;tead of the counterclockwise direction.

With the arrangement illustrated in FIGS. 6 and 7, assuming the arrangement to be an overvoltage relay, the spring 45 will bias the trip finger 35' in a clockwise direction away from engagement with the armature 40' of the circuit breaker. During normal conditions the elec tromagnetic flux produced by the coil 14 is insufficient to attract the armature 22' and the trip finger 35' is maintained in spaced relation with the armature 40' by the bias of the spring 45. Upon a predetermined overvoltage level, the electromagnetic force produced by the coil 14' is sufiicient to attract the armature 22' and to pivot the armature 22' in a horizontal plane, moving the link 75 to the right, as viewed in FIG. 6, causing the trip finger 35 to pivot counterclockwise about the pivot 74' into engagement with the armature 40 and turning the armature 4t) sufficiently to trip the mechanism of the circuit breaker.

Thus, as viewed in FIG. 7, hole 72' is empty whereas in the previous embodiment, as seen in FIG. 5, hole 84 is empty.

The overvoltage relay is maintained in the position shown by FIG. 6 so long as the overvoltage persists in the coil 14. Upon a drop in the overvoltage to a sufficient, lower predetermined level, the force produced by the coil is insufficient to overcome the spring force and the force of the spring 45 returns the trip finger 35' to its initial position to which it is spaced from the armature 40, but this initial position is not illustrated in the drawings for an overvoltage or remotely tripping relay.

The remote tripping operation of a relay constructed in accordance with this invention is similar to that described in connection with FIGS. 6 and 7, however, for remote tripping a switching arrangement (not shown) is provided in the electrical circuit of the coil 14' for energizing the coil 14' momentarily only, i.e., only for a suflicient period of time to actuate the mechanism to the position shown in FIG. 6 and thereafter the coil 14' becomes deenergized, the mechanism returning to its initial position, not illustrated. Thus, it is seen that an advantage of the present construction is that when used for remote tripping, the relay coil 14' need not be normally nor continuously energized.

Since the motion of the armature 22 is a pivoting one in the horizontal plane, and since the trip finger pivots essentially in a vertical plane, being connected to the support brackets 73 or 83 only at one location, i.e., either at the pin 74 (FIG. 5) or at the pin 74' (FIG. 7) there is some tendency for the trip finger 35 or the trip finger 35' to cock. Referring to the trip finger 35 in FIG. 4, this cocking is in a clockwise direction and the right hand side of the trip finger 35 in the vicinity of the bracket 83 tends to engage the bracket 83. For this reason the bracket 83 is made wide enough to provide a long enough surface upon which this part of the trip finger can slide during movement back and forth without im pinging or jamming on the right hand edge of the bracket 83.

Having described this invention, what I claim is:

1. In an electrical relay, the combination comprising an electrical coil, a core of magnetizable material upon which said coil is mounted, an armature, means defining first, second and third support, said armature being pivotally connected to said first support, a trip finger pivotally connected to said second support at one of two positions, a link pivotally connected at one end to said armature and at the other end connected to the other of said two positions to which said trip finger is not connected, and a tension spring connected at one end to said armature and at the other end to said third support.

2. In an electrical relay, the combination comprising an electrical coil, 0. core of magnetizable material upon which said coil is mounted, a horizontally disposed armature, means secured to said core and defining first, secend and third supports, said armature being pivotally conjnected to said first support, a vertically disposed trip finger pivotally connected to said second support at the first of two positions, a link pivotally connected at one end to said armature, said link'being pivotally connected to said trip finger at the second of said two positions, a tension spring connected at one end to said armature and at the other end to said third support, said armature being movable generally in a horizontal plane, and said trip lever being movable generally in a vertical plane, the connection of said trip finger to said second support and thti connection of said link to said trip finger being reversible toalternately spring bias the trip finger in one direction or the opposite direction about its pivotal connection to said second support. I

' 3. In a relay, the combination comprising a coil, a core of magnetizable material upon which said coil is mounted, an armature movable by the electromagnetic flux produced by said coil,,first, second and third supports secured to said core, an armature pivotally connected to said first support, a trip finger for tripping a circuit breaker, said trip finger being pivotally mounted on said second support, a spring secured at one end to said armature and at its opposite end to said third support, a link pivotally connected to said armature at one end and connected to said trip finger at the other end, said trip finger being connected to said second support in bne of two positions, said link being connected to said trip finger in one of'two positions, the force of said spring being applied by said link to said trip finger in the direction to pivot said trip finger about its pivotal connecton to said second support in the direction toward engagement of the trip finger with said circuit breaker when said link and trip finger are in their first positions and in the opposite direction when said link and trip finger are in their second positions.

4. In a relay, the combination comprising a coil, a core of magnetizable material upon which said coil is mounted, an armature movable by the electromagnetic flux produced by said coil, a first support pivotally mounting said armature relative to said core, a trip finger engageable with a trip means of a circuit breaker for tripping thelatter, second, third and fourth supports within said relay, a spring secured at one end to said armature and at its opposite end to said third support, said trip finger being connectable alternately to said sec- .ond or said fourth support, a link connected at one end to said armature, said trip finger having two pivotal mounting means, one of said mounting means being connected to either said second or said fourth support and the other mounting means being connected to the opposite end of said link, the spring force being applied by said link to said trip finger to pivot said trip finger about 8 its pivotal connection to said second support in the direction to bias the trip finger toward engagement of the trip finger with said circuit breaker trip means, and when said trip finger is pivotally connected to said fourth sup- 'port the spring force being applied in the direction to bias the trip finger away from such engagement.

5. In a relay, the combination comprising a coil, a core of magnetizable material upon which said coil is mounted, a horizontally pivotal armature movable in response to the electromagnetic fiuX produced by said coil, a first support pivotally mounting said armature relative to said core, a vertically pivotal trip finger engageable with a trip means of a circuit breaker for tripping the latter, second, third and fourth supports Within said relay, a spring secured at one end to said armature and at its opposite end to said third support, said trip finger being connectable alternately to said second 'or said fourth support, a substantially rigid link to transfer motion between the vertically pivotal trip finger and the horizontally pivotal armature, said link being connected at one end to said armature, said trip finger having two pivotal mounting means, one of said mounting means being connected to either said second or said fourth sup-" port and the other mounting means being connected to circuit breaker trip means, and when said trip finger is pivotally connected to said fourth support the spring force being applied in the direction to bias the trip finger away from said engagement.

6. In a relay, the combination comprising a coil, a core of magnetizable material upon which said coil is mounted, an armature movable by the electromagnetic fiux produced by said coil, a first support support secured within said relay to which said armature is pivotally mounted for movement relative to said core, a'trip finger engageable with a trip means of a circuit breaker for tripping the latter, a second support support mounted within said relay to which said trip finger is pivotally mounted, a link connected to said armature at one end and to said trip finger at the other end at either one side or the other of the pivotal mounting of said trip-finger, a spring biasing said armature so as to pivot said trip finger about its pivotal connection to said second support in the direction toward engagement of the trip finger with said trip means or away therefrom.

No references cited.

BERNARD A. GILHEANY, Primary Examiner. R. N. ENVALL, JR., Assistant Examiner, 

1. IN AN ELECTRICAL RELAY, THE COMBINATION COMPRISING AN ELECTRICAL COIL, A CORE OF MAGNETIZABLE MATERIAL UPON WHICH SAID COIL IS MOUNTED, AN ARMATURE, MEANS DEFINING FIRST, SECOND AND THIRD SUPPORT, SAID ARMATURE BEING PIVOTALLY CONNECTED TO SAID FIRST SUPPORT, A TRIP FINGER PIVOTALLY CONNECTED TO SAID SECOND SUPPORT AT ONE OF TWO POSITIONS, A LINK PIVOTALLY CONNECTED AT ONE END TO SAID ARMATURE AND AT THE OTHER END CONNECTED TO THE OTHER OF SAID TWO POSITIONS TO WHICH SAID TRIP FINGER IS NOT CONNECTED, AND A TENSION SPRING CONNECTED AT ONE END TO SAID ARMATURE AND AT THE OTHER END TO SAID THIRD SUPPORT. 